I have previously written that IELTS Examnation is not mandatory for Federal Skilled Worker applicants. That a written submission or other evidence to support language proficiency may be submitted instead of a third party test like IELTS.
This may change once the proposed Regulations Amending the Immigration and Refugee Protection Regulations (Permanent Residents) concerning the language assessment for Federal Skilled Worker applicants is approved.
The Immigration and Refugee Protection Regulations (IRPR) [section 79] state that federal skilled worker applicants may demonstrate their language proficiency by either submitting the results of a designated third-party language test, or a written submission. Regardless of which option is chosen, both are assessed against one standard in the awarding of language points—the Canadian Language Benchmarks, for English, or the Niveaux de compétence linguistique canadiens 2006, for French. The Department is planning to repeal the option of providing a written submission and require all federal skilled worker applicants to submit the results of third-party language tests as proof of language proficiency. This will also apply to business class immigrants, as they are required to comply with section 79, as stated in paragraph 102(1)(c). The impact on business class immigrants will be minimal, given that they have a substantially lower pass mark. Consequently, very few business class applicants require language points in order to be selected.[Source]
This proposal is being opposed by The Canadian Bar Association saying the mandatory testing is unnecessary and excessively burdensome.
If you are applying for permanent residence in Canada, it is best that you prepare yourself by getting an IELTS Review and Test Simulation before you write the IELTS Examination.